Astronaut Puts Muscle Into Hubble Repair

CAPE CANAVERAL, Fla. - Atlantis astronauts flew to the Hubble Space Telescope this month with more than 100 specially designed tools for work of unprecedented complexity.

But for the second time during the planned 11-day servicing mission, it was a spacewalker's raw strength on Sunday that made it possible to get through a typically routine task and continue on with a critical job.

A single stripped screw eluded the grip of mission specialist Mike Massimino's drill, preventing him from removing an 18-inch handrail that blocked access to a light-splitting Hubble spectrograph in need of repair.

About three hours into the mission's fourth spacewalk, NASA mission managers allowed a frustrated Massimino to give the handrail a hard yank - a move that threatened to break loose debris and expose his spacesuit to jagged edges.

"It's off," Massimino reported after a moment of suspense with no video available to show the results. "Disposal bag, please."

A similar show of strength enabled mission specialist Drew Feustel to loosen a tight bolt on Thursday, paving the way for a powerful new camera to be installed.

Finally, Massimino and partner Mike Good began what was supposed to be the hard work of reviving the Space Telescope Imaging Spectrograph, or STIS, which had been dormant since a power failure in 2004.

When it functioned, the instrument was responsible for about a third of Hubble's science observations, including the surprising discovery that massive black holes are common at the centers of galaxies.

Although a successful repair wasn't required for the mission to claim success, scientists badly wanted the revived spectrograph to complement a state-of-the-art sister instrument installed Saturday.

With the handrail out of the way, Massimino prepared to remove 111 small, loose screws holding a panel over the spectrograph's electronics box.

But his power drill was dead.

"Oh, for Pete's sake," he said, before retrieving a backup drill and refreshing his oxygen supply.

That's when several of the newly designed tools showed their worth. A color-coded capture plate prevented the 111 fasteners from floating away and damaging the sensitive telescope.

With relative ease, Massimino removed the cover panel and installed a new low voltage power supply card.

But the job took more than two hours longer than expected, forcing managers to drop plans to cover a Hubble equipment bay with a new protective blanket.

The work was so arduous that Massimino reported the potentially alarming news that a hole was forming in the palm of his glove. But it wasn't serious enough to force him to retire early.

Telescope operators soon confirmed that the spectrograph's new power source was working, prompting cheers among Atlantis' seven-person crew. Tests of its three science channels were ongoing.

On Monday, mission specialists John Grunsfeld and Feustel will step into space for the mission's fifth and final spacewalk, probably becoming the last people ever to touch Hubble. The observatory was launched in 1990 and serviced by astronauts five times.

More importantly, they hope to achieve some last-but-not-least upgrades, including installation of a second set of fresh batteries and a refurbished guidance sensor that are top mission priorities.

Massimino and Good's spacewalk ended up as the sixth longest ever at just over eight hours. That was six minutes longer than their first spacewalk on Friday, another top-10 effort.